1. Field of the Invention
The present invention relates to anti-electromagnetic interference (anti-EMI) electro-optical modules, and more particularly, to an electro-optical module in which an electro-optical element is electrically connected to an interposer in a flip-chip manner to reduce the size of the electro-optical module.
2. Description of Related Art
Along with the development of semiconductor fabrication technologies, a chip can be integrated with not only electronic elements but also biological, electro-optical, mechanical, electrical or magnetic elements. For example, a laser diode chip is integrated with both electro-optical and electrical functions. There are three types of laser diodes: fabry-perot (FP) laser diodes, distributed feedback (DFB) laser diodes and vertical cavity surface emitting laser (VCSEL) diodes. Since VCSEL diodes are either of a surface emission type or of an edge emission type and can be fabricated with high precision and hence are easier to control than the FP and DFB laser diodes, the VCSEL diodes have become the first choice of the development of electro-optical modules.
Further, the VCSEL diodes generally have an active surface and a plurality of bonding pads at the same side. Therefore, for an electro-optical module having a VCSEL diode, the VCSEL diode is usually electrically connected to a substrate through wire bonding.
FIG. 1 is a schematic cross-sectional view of a conventional electro-optical module 1. Referring to FIG. 1, the electro-optical module 1 has: a substrate 10; a laser diode 111 and a photo diode 112 disposed on the substrate 10 for emitting and receiving light, respectively, wherein the laser diode 111 has an active surface 111a and a plurality of electrode pads 111b, and the photo diode 112 has an active surface 112a and a plurality of electrode pads 112b; a drive/electronic circuit controller (not shown); a plurality of support members 12 disposed on the substrate 10; and a transparent plate 14 disposed on the support members 12 and having lens portions 141, 140 respectively corresponding in position to the active surfaces 111a, 112a. Further, the electrode pads 111b of the laser diode 111 and the electrode pads 112b of the photo diode 112 are electrically connected to the substrate 10 through a plurality of bonding wires 110. However, such a wire bonding method can easily result in signal losses and electromagnetic interferences during high frequency signal transmission.
Therefore, there is a need to provide an electro-optical module to overcome the above-described disadvantages.